Consciousness is a highly evolved brain/mental state that can be described as an organism's awareness of representations of its internal environment. The biological basis for human consciousness remains incompletely understood. There is no scientific agreement on a comprehensive model for consciousness and current theories remain contradictory. It is not clear, for instance, whether consciousness is a single trait, or a mosaic of the brain's individual perceptual processes unified by spatiotemporal binding factors. Similarly, the neurobiology of severe neurologic and psychiatric disorders that disrupt conscious perceptual awareness is not well understood. Elucidating the neural mechanisms underlying specific disorders of conscious perceptual awareness can lead to more specific, biologically-based diagnostic and treatment strategies. The spatiotemporal accuracy of magnetoencephalography (MEG) in combination with positron emission tomography (PET) using carefully designed paradigms and analyses in well characterized patient populations with disorders of perceptual awareness, can provide such important information.